One of the more interesting sales trends seen within Daavlin’s Clinical department has been a slight uptick in conventional UVB broadband lamp machines (also known as “FS” type or color /12 lamps). In our investigation into this phenomena, we have consistently heard two things:
Treatment times for darker skin types are more manageable, especially in combination UVB/UVA phototherapy machines. Much like in narrowband UVB, a patient’s ultimate maximum tolerable broadband UVB dose is somewhere between 6 and 10 times their starting MED. A hypothetical example would be that of a Fitzpatrick skin-type 5 patient with a broadband MED of ~170mJ[1], and a narrowband UVB MED of ~1100mJ[2], might reach final doses of 1020mJ of broadband UVB, and 6600 mJ of narrowband UVB. With typical combination phototherapy machine outputs of 2mW broadband UVB or 5mW narrowband UVB, that might translate to total treatment times around 9 minutes for broadband UVB and 22 minutes for narrowband UVB.
Some less common indications seem to respond better to broadband than narrowband, typically those involving pruritic conditions. There may also be a subset phenotype of psoriatic patients that responds better to broadband UVB than to narrowband, for reasons that are not fully understood at this time.[3] There seems to be two likely differences in mechanisms between broadband and narrowband therapy that could explain this: broadband contains more sub-300nm energy that efficiently produces vitamin D, and it contains some UVA2 content. With respect to Vitamin D production, broadband is far superior to narrowband, as it closely matches the Vitamin D spectrum, consistently raising 25-hydroxy levels in to normal range with as little as ¼ of body surface area exposed to 100mJ of broadband UVB.[4] With respect to the UVA2 content present in a broadband UVB lamp, it is interesting that some centers essentially simulate this by adding UVA to narrowband UVB protocols in atopic dermatitis treatments.[5]
In any case, broadband UVB continues to remain a viable treatment modality, despite 20 years of living in narrowband UVB’s shadow. For more information about broadband UVB, please contact Daavlin today!
[1] Yu-WenLia, Chia-YuChu. The Minimal Erythema Dose of Broadband Ultraviolet B in Taiwanese. Journal of the Formosan Medical Association 2007 106:11, November, 975-978
[2] Ganesh S Pai .Med estimation for narrow band UV-B on type IV and type V skin in India IJDVL. 2001 67:5 251-252/
[3] Rupa Pugashetti, Henry W. Lim & John Koo. Broadband UVB revisited: Is the narrowband UVB fad limiting our therapeutic options? Journal of Dermatological Treatment Vol. 21 , Iss. 6,2010
[4] Osmancevic, et al. Vitamin D production after UVB exposure – a comparison of exposed skin regions.J Photochem Photobiol B. 2015 Feb;143:38-43. doi: 10.1016/j.jphotobiol.2014.12.026. Epub 2015 Jan 6.
[5] Fernández-Guarino, et al. Treatment of moderate and severe adult chronic atopic dermatitis with narrow-band UVB and the combination of narrow-band UVB/UVA phototherapy. Dermatol Ther. 2016 Jan-Feb;29(1):19-23. doi: 10.1111/dth.12273. Epub 2015 Aug 24.
